Not all influencer campaigns are created equal. A weight-loss supplement company, embroiled in legal battles over product recalls, recently reached out to influencer marketer Brett Sosnik hoping to help restore its image. The client wanted a very specific group of social stars to run its influencer campaigns going forward: They had to be overweight female adults — preferably 40 and older — who do not like exercise and with a body mass index over 25.

“All these are very personal information that influencers may volunteer but we typically don’t ask,” said Sosnik, senior account executive for influencer marketing agency Collective Bias.

It took two weeks longer than usual for Sosnik’s team to find 20 influencers that roughly fit the weight loss supplement client’s requirements. Each influencer created two long-form blog posts around their weight-loss journey to showcase product effectiveness. Then they shared the posts with their social circle on Instagram, Facebook or Twitter. This single campaign from start to finish took around two months, while a typical influencer campaign for a fashion brand at the same scale takes around three to four weeks, according to the agency.

Such a lengthy process is typical for influencer marketing in the weight loss supplement space where influencers must discuss the benefits and side effects, as required by the Food and Drug Administration. Branded posts for other categories are less regulated when it comes to the language and images used; content created by an influencer for an over-the-counter medicine or supplement requires legal reviews to make sure that it doesn’t include children or compare different products, for instance. The draft approval process by the client and its legal team often delays an influencer campaign’s live dates significantly.

And since each over-the-counter supplement has a specific intended benefit, it is often hard to find influencers that need or want to use those products, according to Holly Pavlika, svp of marketing and content for Collective Bias.

“You cannot just find a random person to write a post because you need to add context,” said Pavlika. “But the client usually has a very specific demographic in mind, giving us another added variable to be mindful of.”

And often, a weight loss supplement requires the influencer to document life before and after using the supplement, which requires a long commitment to the campaign, so it is not something every influencer will want to do, she added.

Michael Heller, CEO of talent agency Talent Resources, has run influencer campaigns for diet plan SlimFast and weight loss supplement Hydroxycut. Heller said that it would take his team around two months just to identify the right social stars because of clients’ specific age, gender and weight requirements.

“We also have to care about the side effects and if the influencer is pregnant when working with a weight loss supplement client,” said Heller.

Of course, social stars flogging supplements are required to include clear disclosures and follow legal guidelines such as specific uses of a product throughout the post, including about how often to take the pill, the most significant risks of taking the supplement and mandatory call-outs to studies on the product. Such legal regulations are specific to the pharmaceutical industry and can end up with posts looking heavily branded.

During the review process, the client’s legal and medical teams would often ask for changes or edits that were not given to the agency at the campaign outset or may even go against some of the initial guidelines provided by the client, said Collective Bias’ Pavlika. If that’s the case, her team would have to go back and delete portions that help add more personality to the blog posts.

Since there are more watchdogs in the pharmaceutical industry, Heller’s agency doesn’t strike one-off deals with brands in the space.

“There are lots of waivers, so we have to bring in a lawyer,” he said. “Since the threshold is higher, we usually do multiyear deals with pharma clients that entail both digital and print ads, rather than straight-up social campaigns.”